To promote the diesel engine, Cummins Engine Company owner Clessie Cummins mounted a diesel engine in a used Packard Touring Car and set out for the National Automobile Show in America's first diesel-powered automobile in January of 1930.
The 800-mile trip from Indianapolis to New York City used 30 gallons of fuel, which cost $1.38, and showed that diesel was a viable option as an internal combustion engine. It was the first of many diesel-powered driving feats Cummins would attempt and it established his company as an engine supplier that would lead to success in the trucking industry.
The diesel engine became an important replacement for the steam piston engine and was used in submarines, ships, and eventually trains, trucks, and modern cars. Today it's used for high torque and low RPM requirements, and lighter engine designs have been used in some aircraft.